Adds full supposed for Wasm in the swift lib (#7328)

Adds tests for wasm module & github action

tests/FlatBuffers.Test.Swift.Wasm/Package.swift

@@ -0,0 +1,34 @@
+// swift-tools-version:5.1
+/*
+ * Copyright 2020 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import PackageDescription
+
+let package = Package(
+  name: "FlatBuffers.Test.Swift.Wasm",
+  platforms: [
+    .macOS(.v10_14),
+  ],
+  dependencies: [
+    .package(path: "../../swift/"),
+  ],
+  targets: [
+    .target(
+      name: "Wasm"),
+    .testTarget(
+      name: "FlatBuffers.Test.Swift.WasmTests",
+      dependencies: ["FlatBuffers"])
+  ])